Stand establishment refers to the production of a uniform population of healthy seedlings of agricultural crops. The stand of an agricultural crop may be established through direct seeding into the field, or by the planting of transplants. Successful crop production and optimum yields can be accomplished only when maximum stand establishment is achieved. (Grassbaugh et al., 1998, Sci. agric., Piracicaba, 55 (Edicao Especial): 116-120). Stand reduction generally results in reduced yields and variable crop quality. Several factors contribute to stand establishment in the production of agricultural crops. Environmental factors such as drought, temperature stress and unfavorably soil conditions, as well as pathogens and insects that attack seeds and seedlings can all contribute to reduced stands (Orzolek, 1991, HortTechnology 1: 78-81). For direct-seeded crops, uneven germination results in seedlings of various sizes and gaps in the planting row, which can ultimately result in reduced yields. For transplanted crops, poor transplant survival rates or slow initiation of plant growth after transplanting can result in reduced plant populations and uneven stands. In addition, cultural practices such as herbicide and insecticide applications after transplanting or seed emergence may be less effective in fields having nonuniform growth (Bennett et al., 1992, HortTechnology 2(3): 345-349). Plants of different sizes within a field population may also cause problems in timing sidedress applications of fertilizers (Ford, 1987, Crops and Soils Magazine, p. 12-13, April/May, 1987). Thus, measures to lessen the impact of environmental stresses and various pests are vital in the successful establishment of agricultural crop stands. The ability of plants to survive stresses imposed by environmental conditions and pest infestations greatly depends on the initial vigor of the stand at establishment.
Dry seed coating is one method that has been developed to improve establishment of direct-seeded crops. For example, US 2012/0220454 describes seed coating compositions that may comprise more than one layer, for example, a first layer comprising a film forming layer, a second layer comprising a binding agent, and a third layer comprising a wetting agent. See US 2012/0220454, paragraph [0019]. In addition US 2012/0220454 teaches that the seed coating compositions can flow better through a seeding mechanism, because their surface is smoother than that of non-coated seed. See US 2012/0220454, paragraph [0021].
US 2010/0267554 describes coating seeds with a wetting agent such as copolymers, block copolymers, alcohol ethoxylates, nonylphenol ethoxylates, ethylene oxide/propylene oxide block copolymers, and alkylpolyglycosides for planting in hydrophobic soils. See US 2010/0267554, paragraphs [0022] and [0023].
Despite the potential advantages of seed coating technologies, a need still exists for improving stand establishment for direct-seeded and transplanted food crops and ornamental plants.